Occurrence of autoantibodies against thyroglobulin in Norwegian dogs.

Serum samples from 45 hypothyroid dogs, 11 clinically healthy dogs and 31 dogs with various clinical endocrinopathies, seborrhoea and dermatitis were tested for thyroglobulin antibodies using the passive hemagglutination test. A chromic chloride (CCH)- and a glutaraldehyde (GCH) method were used in the assay. Circulating antibody titer against thyroglobulin were observed in 34 % and 24 % of dogs with hypothyroidism by the CCH and the GCH method, respectively. Three of 12 dogs with seborrhoea had low titers (20 to 40) of thyroglobulin antibodies. Thyroglobulin antibodies were observed in 1 of 3 hypothyroid dogs with thyroid carcinoma. Clinically healthy dogs and dogs with certain other endocrinopathies (Addison’s disease, Cushing’s disease, Diabetes mellitus, Hyperestrogenism) and dermatitis were negative. Though the CCH method detected thyroglobulin antibodies in more serum samples than the GCH method, the GCH method was considered more reliable in that the glutaraldehyde treated cells were more stable, both at room temperature and at +4°C.